Can we create 3D a new type of animal and have many thousands in a game, but each one of them is a unique design?

I want to create many thousands of new type animal. Each one of them is unique design because they will be fed differently by game player… how I can create them??? For example, how I can create 10,000 new type of dogs, but they are a bit different and each one of them might changeable in the future because of the result of feeder (game player). Then I might put those dogs in a game to grow, train and fight to other dog eventually.

I’ve never tried doing this, but I’m guessing the solution to this would be procedural simulations, do some research online and see if you can find anything related to your topic.